Can't see animation after exporting to video
Hover your cursor over the grid and key Esc until the grid goes away (probably twice).

What has happened is that because you selected Image Editor in the Properties panel > Render tab > Render dropdown, your computer rendered your video by switching the screen that was previously there (a 3D Viewport) to a UV/Image Editor.

I generally select New Window, because then you can simply X out of the window once it is done.